valueFromAST: fixed coercing of null variables on non-nullable… (#2348)

Author: IvanGoncharov

src/utilities/__tests__/valueFromAST-test.js

@@ -72,6 +72,7 @@ describe('valueFromAST', () => {
     expectValueFrom('"BLUE"', testEnum).to.equal(undefined);
     expectValueFrom('null', testEnum).to.equal(null);
     expectValueFrom('NULL', testEnum).to.equal(null);
+    expectValueFrom('NULL', new GraphQLNonNull(testEnum)).to.equal(null);
     expectValueFrom('NAN', testEnum).to.deep.equal(NaN);
     expectValueFrom('NO_CUSTOM_VALUE', testEnum).to.equal('NO_CUSTOM_VALUE');
   });
@@ -184,6 +185,7 @@ describe('valueFromAST', () => {
     expectValueFrom('$var', GraphQLBoolean, {}).to.equal(undefined);
     expectValueFrom('$var', GraphQLBoolean, { var: true }).to.equal(true);
     expectValueFrom('$var', GraphQLBoolean, { var: null }).to.equal(null);
+    expectValueFrom('$var', nonNullBool, { var: null }).to.equal(undefined);
   });
 
   it('asserts variables are provided as items in lists', () => {

src/utilities/valueFromAST.js

@@ -50,18 +50,6 @@ export function valueFromAST(
     return;
   }
 
-  if (isNonNullType(type)) {
-    if (valueNode.kind === Kind.NULL) {
-      return; // Invalid: intentionally return no value.
-    }
-    return valueFromAST(valueNode, type.ofType, variables);
-  }
-
-  if (valueNode.kind === Kind.NULL) {
-    // This is explicitly returning the value null.
-    return null;
-  }
-
   if (valueNode.kind === Kind.VARIABLE) {
     const variableName = valueNode.name.value;
     if (!variables || isInvalid(variables[variableName])) {
@@ -78,6 +66,18 @@ export function valueFromAST(
     return variableValue;
   }
 
+  if (isNonNullType(type)) {
+    if (valueNode.kind === Kind.NULL) {
+      return; // Invalid: intentionally return no value.
+    }
+    return valueFromAST(valueNode, type.ofType, variables);
+  }
+
+  if (valueNode.kind === Kind.NULL) {
+    // This is explicitly returning the value null.
+    return null;
+  }
+
   if (isListType(type)) {
     const itemType = type.ofType;
     if (valueNode.kind === Kind.LIST) {